Zoned elevator system



Dec. 16, 1952 Filed Aug. 29, 1951 W. H. ESSELMAN ZONED ELEVATOR SYSTEM 2 SHEETSSl-IEET 2 L+7 L-7 -L+8 L-8' System of Patent 23762l8 Modified as shown in Dot and Dosh Outline WITNESSES: INVENTOR gdW/Zy WclterHEsselmun.

ATTORNEY Patented Dec. 16, 1952 ZONED ELEVATOR SYSTEM Walter H. Esselman, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 29, 1951, Serial No. 244,113

Claims. 1

This invention relates to apparatus having a response to a variable quantity, which response varies in a predetermned manner, and it has particular relationship to an elevator system utilizing such apparatus for controlling the elevator system in accordance with the demand for elevator service. Inasmuch as the invention is particularly suitable for an elevator system, it will be described with reference thereto.

In certain elevator systems, apparatus is required having a response to a variable quantity, which response varies in a predetermined manner with the operation of the apparatus. For example in the Williams et a1. Patent 2,376,218, a quota relay is employ-ed having an energization dependent on the number of registered down floor calls. The quota relay is designed to pick up initially when a predetermined number' of down floor calls, such as two calls are registered. Upon registration of two or more such calls the quota relay thereupon operatesto condition one of the elevator cars for assignment to the low zone of floors. In addition to assigning one of the elevator cars to the low zone, the quota relay so modifies its energizing circuit that a larger total number of down floor calls are required to pick up the quota relay. Consequently, a larger number of down floor calls, such as four floor calls, may be required for the purpose of picking up the quota relay again to assign a second elevator car to the low zone of floors.

In accordance with the invention, translating means, such as a quota relay, is energized from the output of a bridge circuit. One of the arms of the bridge circuit has an impedance which is dependent on a predetermined variable quantity, such as the number of registered down floor calls in an elevator system for the purpose of unbalancing the bridge circuit in a direction suitable for operating the translating means. The operation of the translating means introduces an unbalance in the bridge circuit which is in a direction opposing further operation of the translating means. In this way, an operation of the translating means increases the bias impeding further operation of the translating means.

In addition, an adjustable impedance is included in one of the arms of the bridge circuit which may be manually operated for the purpose of adjusting the balance of the" bridge circuit. Such a balance readily may beobtained, and the resulting bridge circuit is relatively insensitive to variations in the energy applied thereto.

It is ther fore an Obj t of the invention to provide improved apparatus responsive to a variable quantity wherein the response varies in a predetermined manner with the operation of the apparatus.

It is a further object of the invention to provide apparatus as set forth in the preceding paragraph wherein translating means is energized from the output of a bridge circuit.

It is an additional object of the invention to provide an elevator system wherein the service provided by an elevator system is controlled by translating means energized from a bridge circuit and wherein one arm of the bridge circuit has an impedance which varies in accordance with a variable quantity and wherein the balance of the bridge is varied in response to an operation of the translating means.

It is also an object of the invention to provide an elevator systemas defined in the preceding paragraph wherein the impedance of one arm of the bridge circuit is a function of the calls for service from floors served by the elevator system and wherein the impedance of another arm of the bridge circuit is dependent on the operation of the translating means.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawingsrin which:

Figure 1 is a schematic view of a control circuit embodying the invention;

Fig. 2A is a schematic view of an elevator system embodying the invention; and,

Fig. 2B is a schematic view showing in whole or in part certain relays or electromagnetic switches employed in the system of Fig. 2A. If Figs. 2A and 2B are placed in horizontal alignment, it will be found that corresponding contacts and coils of the two figures are substantially in horizontal alignment.

Referring to the drawings, Fig. 1 shows translating means in the form of a relay NN which is to be energized for certain control purposes. To this end the relay NN is energized in accordance with the output of a bridge circuit N having four arms NAI, NA2, NA3 and NA4.

Each of the arms of the bridge circuit may include suitable impedance. Thus, the arm NAI has an impedance represented by resistors NRI to NE! 5, inclusive, which are connected in series. Each of the resistors NRI to NRI5, inclusive, is shunted respectively by means of a switch or contacts Ni to N l5. If the circuit of Fig. 1 is employed for controlling an elevator system, each of the switches NI to Nl5 may correspond to one associated floor. As hereinafter pointed out, the switches NI to NH) may represent contacts of electromagnetic relays, but for present purposes, it will be assumed that each of the switches or contacts NI to NI5 is manually operated and is opened as long as a call for service is registered for the associated floor. From this discussion it will be clear that the impedance of the arm NAI depends on the number of calls for service from the floors served by the elevator cars.

The arm NAZ of the bridge circuit has an impedance represented by resistors NRIG to NRZI, which are connected in series. Again, certain of these resistors are arranged to be shunted by switches or contacts. For example, the resistors NRI8 and NRI9 are shunted by a switch or contacts YA. The resistors NR2!) and NRZI are shunted by a switch or contacts EYA. Resistors NR22 and NR23 are shunted by a switch or contacts CYA. Resistors NR and NR25 are shunted by a switch or contacts DYA. Resistors NRZS and NR2'I are shunted by a switch or contacts EYA. It will be assumed that one of the switches or sets of contacts YA to EYA is operated for each operation of the relay NN. In an elevator system, these switches may correspond to elevator cars which are assigned to provide special service for registered floor calls. For present purposes, it will be assumed that one of the switches or sets of contacts is manually operated for every operation of the relay NN. It will be noted that each operation of one of the switches or sets of contacts YA to EYA modifies the impedance of the arm NAZ. Under certain cases, it may be desirable to modify the amount of unbalance introduced by such operations. To this end, the resistors NRI8, NR20, NRZZ, NR24 and NR26 are shunted by contacts NCZ to NC6, respectively. These contacts may be manually opened or closed independently or each other, or they may be operated as a group. In the present case, it is assumed that these switches or contacts are connected to a common operating member for operation as a group.

It will be noted that the arm NA2 of the bridge 2.

circuit also includes the resistors NRI 0 and NRI I. The resistor NRIG is shunted by a switch or set of contacts NCI which may be connected to the common operating member for the switches or contacts N02 to NC6.

The arm NA3 of the bridge circuit has an impedance represented by a single resistor NRZB. The arm NA4 of the bridge circuit has an impedance represented by a resistor NR29 and by an adjustable resistor NR30 which is connected in series with the resistor N329.

The bridge circuit N has a source of direct current energy connected across one diagonal as represented by the conductors NLI which may be connected to the positive terminal of a direct current source of electrical energy and by a con ductor NLZ which may be connected to the negative terminal of the source.

The output of the bridge circuit is derived through conductors N I I and NI 9 and is employed for controlling the energization of the relay NN. Although the relay may be directly energized from the bridge output, preferably the relay is energized through a device NT having output electrodes NTI and NTZ and having a control electrode NT3 for controlling the current passed between the output electrodes. The device NT may be, for example, a high vacuum electronic tube, but preferably it is a gaseous tube, such as the well known thyratron. It will be noted that the output of the bridge circuit is connected across the control electrode of the grid and the output electrode or cathode NT2 of the thyratron. When the bridge circuit is in the condition illustrated in Fig. 1, a negative bias is applied therefrom to the thyratron for the purpose of preventing the flow of current therethrough. A, source of alternating voltage represented by conductors NL4 and NL5 may be connected across the thyratron NT and the relay NN in series. A capacitor N23 may be connected across the relay NN for the purpose of converting the pulsating energization of the relay NN into a more continuous energization.

The arm NAI of the bridge circuit may have a maximum impedance of resistance equal to that of the resistors NRI8 to NRZ'I, inclusive. However, since the arm NAZ contains additional resistance, the two arms are not balanced, and when the circuit is in the condition illustrated in Fig. 1, the control electrode or grid NT3 of the thyratron is maintained negative relative to the cathode to prevent the flow of current between the output electrodes of the thyratron. As rep resentative of suitable values, each of the resistors NRI to NRI5 may have a value of 10,000 ohms. Each of the resistors NRIB, NRI8, N'RZO, NRZZ, NR24 and NR26 may have a resistance of 10,000 ohms. Each of the resistors NRII, NRIQ, NRZI, NR23, NR25 and NRZ'I may have a resistance of 20,000 ohms. The resistor NR28 and the resistor NR2!) may be 40,000 ohms. The resistor NR3 may be adjustable up to a resistance of 8,000 ohms.

The operation of the control circuit illustrated in Fig. 1 will now be considered. As previously explained with the parts in the conditions illustrated in Fig. 1, a negative bias is applied to the thyratron tube NT, and the relay NN is deenergized. If calls for service are registered for the first and second floors, the switches or sets of contacts NI and N2 will be opened to introduce the resistors NRI and. NR2 effectively into the arm NAI of the bridge circuit. These re sistors have a total value of resistance equal to that of the resistor NRI'I. Since the bridge circuit now is substantially balanced, the negative bias is removed from the thyratron NT, and the relay NN is energized. If an adjustment of the balance of the bridge circuit is required, it may be provided by suitable adjustment of the resistor NRI'lU.

It will be assumed that upon energization of the relay NN. one of the switches or sets of contacts YA to EYA opens. For example, if the switch or set of contacts YA opens, the resistor NRIQ is introduced effectively into the arm NA2 of the bridge circuit. Consequently, the bridge circuit again is unbalanced in a direction applying a negative bias to the control electrode or the grid of the thyratron tube NT, and the relay NN is deenergized.

Next, it will be assumed that additional calls are registered for the third and fourth floors, resulting in an opening of the switches or sets of contacts N3 and N4. The resultant introduction of the resistors NR3 and NR4 in the arm NAI of the bridge circuit restores the balance of the circuit, and the negative bias is removed from the grid or control electrode of the thyratron tube NT to again permit energization of relay NN. However, it will be noted that a total of four calls for service now is required for the energization of the relay NN.

The energization of the relay NN is followed by opening of one of the sets of contacts or switches BYA to EYA which will be assumed to ing a negative bias to the thyratron tube. Relay NN consequently again is deenergized. To reenergize the relay NN under these circumstances, calls for service must be registered for at least six floors.

From the foregoing discussion, it is clear that the energization of relay N is dependent on the registration of floor calls and that the bias introduced by the arm NA2 of the bridge circuit increases for each operation of the relay NN. The resistors NRl'l, NRIS, NRZI, NR23, NR and NR2! were proportioned to have resistances equal to that introduced in arm NAI by registration of two floor calls. However, values of resistance may be employed requiring registra tion of other numbers of floor calls. Furthermore, the resistance values may be weighted or varied for certain floors, and the resistors associated with the switches or sets of contacts YA to EYA may be weighted or varied.

If the contacts NCI to NCB are opened, the associated resistors are introduced into the arm NAZ. The efiect of such opening is to require a larger number of registered down floor calls for each operation of the relay NN. For the previously mentioned typical resistor values, a total of three down floor calls or more would be required for the initial operation of relay NN. The total number of calls required would be increased by three for each operation of one of the switches or sets of contacts YA to EYA.

The complete application of the invention to an elevator system is illustrated in Fig. 2A. In order to simplify the description of the system, it is assumed that the invention is applied to the system illustrated and described in the aforesaid Williams et al. Patent 2,376,218. The system embodying the invention is identical with that illustrated in the aforesaid Williams et a1. patent except for that portion of the system illustrated in Fig. 6 of the Williams et al. patent. For this reason, Fig. 6 of the Williams et al. patent is reproduced here in Fig. 2A, as modified to incorporate the invention.

The following apparatus is illustrated in full or in part in both the Williams et al. patent and the present Fig. 2A.

J-high call reversing relay H-high car call relay K-high floor call relay Wup-direction preference relay KN-no floor call relay DR-door relay Y-quota adjusting relay Z-limiting relay 2 'I-by-pass switch l9-zoning switch 26-parking fioor cam switch L+'|, L-l-direct current buses To facilitate an understanding of the invention, a. brief review will be given of the operation of the elevator system represented by Fig. 2A. It will be recalled that this system includes a plurality of elevator cars which are identified by the letters A, B and C. Components of the system associated with the elevator car A are identified by suitable reference characters. Corresponding components for each of the remaining elevator cars are identified by the same reference characters preceded by the letter corresponding to the associated car. For example, the reference character Y3 designates the third set of contacts for the quota adjusting relay Y of the car A. The contacts BY3 represent the corresponding set of contacts for the car B. The contacts CY3 designate the corresponding set of contacts for the car C.

The zoning switch [9 determines whether the elevator car is assigned for high zone or low zone operation. If the switch is open, the elevator car is assigned for high zone operation and answers all calls for service assigned in the up direction and in the down direction.

If the zoning switch I9 is closed, the elevator car A is assigned for low zone service. Under these conditions, the elevator car is subject to control by the quota relay Q. If a predetermined number of calls for down service are registered in the low zone of floors, the quota relay Q is energized and in turn energizes the quota ad'- justing relay Y. As a result of this operation, if the elevator car A is traveling up in the low zone of floors, it is conditioned to reverse at the highest down floor call in the low zone of floors. This assumes that no floor calls are registered in the car A for a higher floor. If the assignment occurs while the elevator car A is traveling up in the high zone of floors, the elevator car A is conditioned to reverse at the next down floor call which it reaches. This again assumes that no car call is registered in car A for a higher floor.

The operation of the quota adjusting relay Y also increases the total number of down floor calls required to energize again the quota relay Q after the aforesaid assignment of the elevator car A for the purpose of assigning a second elevator car to provide special service for the low zone of floors. A more complete discussion of the operation of the system will be found in the aforesaid Williams et a1. patent.

In Fig. 2A the changes introduced in the Williams et al. system concern the circuits for energizing the quota relay Q. All such changes are enclosed within the dotted rectangle RE of Fig. 2A. It will be noted that the quota relay Q in Fig. 2A is energized through appropriate contacts Y3, BY3, CY3, ZI, BZI and CZI in the manner discussed in the Williams et al. patent. However, the energization for the relay Q is derived from a source of alternating current NAC which may be the conventional power source of alternating current having a frequency of 60 cycles per second, and the energization of relay Q is controlled by the thyratron tube NT, which was discussed in connection with Fig. 1.

It will be recalled from the discussion of Fig. 1 that the grid bias for the thyratron tube NT is derived from a bridge circuit. The bridge circuit of Fig. 2A includes four arms Nal, M12, M13 and NM which correspond, respectively, to the arms NAI, NA2, NA3 and NA4 of Fig. 1. Since the quota relay Q of Fig. 2A is controlled by the down floor calls for only the second, third, fourth and fifth floors, only the resistors NR2, NR3, NR4 and NR5 are shown for these floors in the arm Nal. These resistors are shunted by contacts 2DR4a, 3DR4a, 4DR4a and 5DR5a, which correspond, respectively, to the contacts N2 to N5 of Fig. 1.

It will be noted that the break contacts ZDRda, 3DR4a, 4DR4a, 5DR5a replace the make contacts 2DR4 to 5DR5 respectively, shown in Fig. 6 of the Williams et al. patent. They are, however, operated by the same down call storing relays.

The arms N113, Nail of the bridge circuit shown in Fig. 2A correspond to the arms NAS and NAG of Fig. 1 and may have similar resistance values. The contacts Y2a, BYZa, CYEa of Fig. 2A correspond to the contacts Y, BY and CY of Fig. 1 and have similar resistors associated therewith. The arm NaZ also includes the resistors NRI B and NRI'I shown in Fig. 1. It will be noted that the break; contacts Y2 a, BYZa, CYZa replace the make contacts Y2, BY2 and CYZ respectively of Fig. 6 of the Williams et al. patent, but are operated by the same relays Y, BY and CY.

It will be observed further that the switches NCI, NCZ, N03 and N04 of Fig. 1 also are em ployed in the same way in Fig. 2A.

To illustrate the operation of the system illustrated in Fig. 2A, it will be assumed that the zoning switch I9 is closed to condition the elevator car A for zone operation and that the switches NCI to N04 are closed. With the parts otherwise in the conditions illustrated in Fig. 2A, a negative bias is applied to the tube NT and the quota relay Q is deenergized. If down floor calls subsequently are registered for the second and third floors, the break contacts ZDRM and tDR ia open to introduce the resistors NR2 and NR3 effectively in the arm Nal of the bridge circuit. This balances the resistance NRI'I and consequently removes the negative bias from the thyratron tube to permit energization of the quota relay Q.

The quota relay Q operates in the manner set forth in the Williams et a1. patent to assign the elevator car to provide special service for the low zone of floors. Such conditioning involves the energization of the quota adjusting relay Y which opens its contacts YZa to introduce additional resistance in the arm Nail of the bridge circuit. The resulting unbalance of the bridge circuit restores the negative bias for the thyratron tube, and the quota relay Q is deenergized. A total of four down floor calls now will be required to energize again the quota relay Q.

If the switches NCI to NC4 are open, the number of down fioor calls required for each operation of the quota relay Q would be increased in the manner discussed with reference to Fig. 1.

Although the invention has been described with reference to certain specific embodiments thereof, numerous modifications falling within the spirit and scope of the invention are possible.

I claim as my invention:

1. In an elevator system for serving a plurality of floors of a structure. a call registering device for each of said floors, a bridge circuit having four arms, means for varying the impedance of a first one of the arms as a function of the calls registered by the call registering devices, translating means responsive to the output impedance of the bridge circuit, and means controlled by the translating means for varying the impedance of a second one of the arms.

2. An elevator system as claimed in claim 1 in combination with means for adjusting the impedance of one of said arms.

3. An elevator system as claimed in claim 1 wherein the translating means comprises a device having a pair of output electrodes and a control electrode for controlling current passing between the output electrodes, and connections for biasing the control electrode relative to one of the output electrodes in accordance with the balance of the bridge circuit.

4. In an elevator system for serving a plurality of floors of a structure, a bridge circuit, means for varying the balance of the bridge circuit in a first direction in accordance with variations in a predetermined demand for elevator service, translating means responsive to the balance of the bridge circuit, and means controlled by the translating means for varying the balance of the bridge circuit in a direction opposite to the first direction.

5. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars for serving said floors, call registering means for registering calls for elevator service for the floors of the structure, and service means responsive to predetermined demands for service from the call registering means for providing special elevator service, said service means comprising a bridge circuit, translating means responsive to the bal ance of the bridge circuit, means for varying the balance of the bridge circuit in a first direction as a function of the calls registered by the call registering means to operate the translating means, means responsive to operation of the translating means for assigning one of the elevator cars to provide special elevator service, and means responsive to assignment of each of the elevator cars to provide special elevator service for varying the balance of the bridge in a second direction opposite to the first direction to require an additional service demand before an additional elevator car can be assigned for special service.

5. An elevator system as claimed in claim 5 wherein said bridge circuit has an arm containing a manually-adjustable impedance by which the balance of the bridge circuit may be adjusted.

7. An elevator system as claimed in claim 5 in combination with means operable for adjusting the variation in unbalance of the bridge circuit in the second direction introduced by said assignment of each of the elevator cars to provide special elevator service.

8. An elevator system as claimed in claim 5 wherein the translating means comprises a device having output electrodes and a control electrode for controlling the current passing between the output electrodes, and means for biasing the control electrode relative to one of the output electrodes in accordance with the balance of the bridge circuit.

9. A control device comprising a bridge circuit having first, second, third and fourth arms connected in a loop, translating means connected across an output diagonal of the bridge circuit, said first arm comprising a plurality of first resistors connected in series, a separate first switch individually operable for shunting each of the resistors, the second arm comprising a plurality of second resistors connected in series, a separate second switch individually operable for shunting each of the second resistors, and third switch means for shunting portion of each of the second resistors.

10. A device as claimed in claim 9 wherein the translating means comprises a device having output electrodes and a control electrode for controlling passage or electric current between the output electrodes, said control electrode being connected to be biased relative to one of the output electrodes in accordance with the voltage across said diagonal.

WALTER H. ESSELMAN.

No references cited. 

